Postler shouldn't download attachments along with new messages

I completely agree on that, Postler should definitely download attachments only when asked (maybe when clicking on the attachment?)

This is essentially impossible with our current backend, I have been thinking about writing a new custom backend for Postler however...

In my opinion the automatic attachment download shouldn't be removed but rather presented to the user as an option in the account settings.

For mobile laptop users, both kinds of behaviour are good -- at different times. Like when on broadband, it's great to get attachments downloaded so one is able to work with them when offline. OTOH, when using GPRS, every saved byte counts, so it makes sense to download just headers and everything else on demand.

Maybe it would make sense to:
- develop some heuristics to decide, if postler should download just headers, header and body or full message
- download headers first so user can see his/her emails as soon as possible and then download bodies/attachments in background.

There are two cases here basically where attachments and large messages would be undesirable:

1. slow GPRS, slow dial-up
2. expensive UMTS or WCDMA, per-minute or per-kilobyte fixed line

So ideally we can ask for example connman for the data plan. It has the information but I don't know if/ how applications can find that out.

Alternatively a ‘Don't fetch attachments automatically’ option could be provided.

The current behaviour should remain the default in any case. I expect that in the future we can also fetch headers separately, but that may not happen soon.

Perhaps a third case:
- very large attachments (even if the network connection is not extremely slow, case 1, or expensive, case 2)

What about providing a checkbox option ‘Don't fetch automatically attachments bigger than ..’ (and provide several options in a combobox, say 100KB, 250KB, 500KB, 1MB, 2MB, 5MB)? Would this be unnecessarily complicated?

When I reported this bug my main concern was that Postler could start indiscriminately downloading big to huge attachments, hogging my bandwidth and disk space. In principle, I'm not against its downloading relatively small attachments, and I would actually welcome it. So a 'Don't fetch bigger than' option could be very handy.

A small remark regarding connman: it may easily fail to detect the case of slow DSL connections. The Wifi connection at my university is sometimes slower than the very slow dial-up connection that I had in my infancy at home. I sure wouldn't want Postler to start downloading big attachments on this connection. :)

Specifying in steps how large attachments sounds tredious. You don't want to keep an eye on the size of your attachments, write up a table and switch depending on where you are and perhaps after having performed rudimentary performance measurements of the network, depending on hour and day...

Actually I wonder about Postler remembering if you disabled attachment fetching *for this particular network*, or offer to do so.